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OBJECTIVES: Leukocyte adhesion deficiency is a rare primary immune disorder caused by defects of the CD18 beta-integrin molecule on immune cells. The condition usually presents in early infancy and is characterized by deep tissue infections, leukocytosis with impaired formation of pus, and delayed wound healing. Allogeneic hematopoietic stem-cell transplantation offers the possibility of curative therapy, and with patient numbers at any individual center being limited, we surveyed the transplant experience at 14 centers worldwide. METHODS: The course of 36 children with a confirmed diagnosis of leukocyte adhesion deficiency who underwent hematopoietic stem-cell transplantation between 1993 and 2007 was retrospectively analyzed. Data were collected by the registries of the European Society for Immunodeficiencies/European Group for Blood and Marrow Transplantation, and the Center for International Blood and Marrow Transplant Research. RESULTS: At a median follow-up of 62 months (extending to 14 years), the overall survival rate was 75%. Myeloablative conditioning regimens were used in 28 patients, and reduced-intensity conditioning in 8 patients, with no deaths in this subgroup. Survival rates after matched family donor and unrelated donor transplants were similar, with 11 of 14 matched family donor and 12 of 14 unrelated donor recipients alive; mortality was greatest after haploidentical transplants, after which 4 of 8 children did not survive. Twenty-seven transplant recipients were alive, with full donor engraftment in 17 cases, mixed multilineage chimerism in 7 patients, and mononuclear cell-restricted chimerism in an additional 3 cases. CONCLUSIONS: Hematopoietic stem-cell transplantation offers long-term benefit in leukocyte adhesion deficiency and should be considered as an early therapeutic option if a suitable HLA-matched stem-cell donation is available. Reduced-intensity conditioning was particularly safe, and mixed-donor chimerism seems sufficient to prevent significant symptoms, although careful long-term monitoring will be required for these patients. [ABSTRACT FROM AUTHOR]

Focuses on the naturally occurring primary deficiencies of the immune system. Information on severe combined immunodeficiencies; T-cell immunodeficiencies; Inherited diseases resulting in defective control of lymphocyte activation.

The article offers information on the function of retroviral vectors in gene therapy. Retroviral vectors are attractive instruments for gene therapy of genetic diseases because they enable stable, efficient transgene insertion with a controlled copy. Moreover, after retroviral integration, impacted precursors can transcribe dangerous genes at much higher frequencies.

The article informs that GvHD, which was the main limitation of allogeneic hematopoietic stem cell transplantation (HSCT), has been almost completely eliminated by extensive depletion of donor T cells from the graft combined with profound immunosuppressive treatment. However, the consequence of these non-specific strategies is a long-lasting immunodeficiency associated with increased incidence of disease relapse, graft rejection and reactivation of viral infections. It informs that over the last 10-15 years a number of research teams in Europe and North America have worked out various alloselective approaches from first principles, through translational research to clinical trials.

The Accreditation Subcommittee of the EBMT regularly publishes special reports on current practice of haemopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred since the first report was published in 1996. Haemopoietic stem cell transplantation today includes grafting with allogeneic and autologous stem cells derived from bone marrow, peripheral blood and cord blood. With reduced intensity conditioning regimens in allogeneic transplantation, the age limit has increased, permitting the inclusion of older patients. New indications have emerged such as autoimmune disorders and AL amyloidosis for autologous, and solid tumours for allogeneic transplants. The introduction of alternative therapies has challenged well-established indications such as imatinib for chronic myeloid leukaemia. An updated report with revised tables and operating definitions is presented here.Bone Marrow Transplantation (2006) 37, 439–449. doi:10.1038/sj.bmt.1705265; published online 30 January 2006 [ABSTRACT FROM AUTHOR]

Patients with X-linked severe combined immunodeficiency (SCID-X1) were successfully cured following gene therapy with a gamma-retroviral vector (gRV) expressing the common gamma chain of the interleukin-2 receptor (IL2RG). However, 5 of 20 patients developed leukemia from activation of cellular proto-oncogenes by viral enhancers in the long-terminal repeats (LTR) of the integrated vector. These events prompted the design of a gRV vector with self-inactivating (SIN) LTRs to enhance vector safety. Herein we report on the production of a clinical-grade SIN IL2RG gRV pseudotyped with the Gibbon Ape Leukemia Virus envelope for a new gene therapy trial for SCID-X1, and highlight variables that were found to be critical for transfection-based large-scale SIN gRV production. Successful clinical production required careful selection of culture medium without pre-added glutamine, reduced exposure of packaging cells to cell-dissociation enzyme, and presence of cations in wash buffer. The clinical vector was high titer; transduced 68-70% normal human CD34+ cells, as determined by colony-forming unit assays and by xenotransplantation in immunodeficient NOD.CB17-Prkdcscid/J (nonobese diabetic/severe combined immunodeficiency (NOD/SCID)) and NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NOD/SCID gamma (NSG))) mice; and resulted in the production of T cells in vitro from human SCID-X1 CD34+ cells. The vector was certified and released for the treatment of SCID-X1 in a multi-center international phase I/II trial. [ABSTRACT FROM AUTHOR]

Severe combined immunodeficiency (SCID) patients with an inactivating mutation in recombination activation gene 1 (RAG1) lack B and T cells due to the inability to rearrange immunoglobulin (Ig) and T-cell receptor (TCR) genes. Gene therapy is a valid treatment option for RAG-SCID patients, especially for patients lacking a suitable bone marrow donor, but developing such therapy has proven challenging. As a preclinical model for RAG-SCID, we used Rag1-/- mice and lentiviral self-inactivating (SIN) vectors harboring different internal elements to deliver native or codon-optimized human RAG1 sequences. Treatment resulted in the appearance of B and T cells in peripheral blood and developing B and T cells were detected in central lymphoid organs. Serum Ig levels and Ig and TCR Vβ gene segment usage was comparable to wild-type (WT) controls, indicating that RAG-mediated rearrangement took place. Remarkably, relatively low frequencies of B cells produced WT levels of serum immunoglobulins. Upon stimulation of the TCR, corrected spleen cells proliferated and produced cytokines. In vivo challenge resulted in production of antigen-specific antibodies. No leukemia development as consequence of insertional mutagenesis was observed. The functional reconstitution of the B- as well as the T-cell compartment provides proof-of-principle for therapeutic RAG1 gene transfer in Rag1-/- mice using lentiviral SIN vectors. [ABSTRACT FROM AUTHOR]

Hurler's syndrome (HS), the most severe form of mucopolysaccharidosis type-I, causes progressive deterioration of the central nervous system and death in childhood. Allogeneic stem cell transplantation (SCT) before the age of 2 years halts disease progression. Graft failure limits the success of SCT. We analyzed data on HS patients transplanted in Europe to identify the risk factors for graft failure. We compared outcomes in 146 HS patients transplanted with various conditioning regimens and grafts. Patients were transplanted between 1994 and 2004 and registered to the European Blood and Marrow Transplantation database. Risk factor analysis was performed using logistic regression. ‘Survival’ and ‘alive and engrafted’-rate after first SCT was 85 and 56%, respectively. In multivariable analysis, T-cell depletion (odds ratio (OR) 0.18; 95% confidence interval (CI) 0.04–0.71; P=0.02) and reduced-intensity conditioning (OR 0.08; 95% CI 0.02–0.39; P=0.002) were the risk factors for graft failure. Busulfan targeting protected against graft failure (OR 5.76; 95% CI 1.20–27.54; P=0.028). No difference was noted between cell sources used (bone marrow, peripheral blood stem cells or cord blood (CB)); however, significantly more patients who received CB transplants had full-donor chimerism (OR 9.31; 95% CI 1.06–82.03; P=0.044). These outcomes may impact the safety/efficacy of SCT for ‘inborn-errors of metabolism’ at large. CB increased the likelihood of sustained engraftment associated with normal enzyme levels and could therefore be considered as a preferential cell source in SCT for ‘inborn errors of metabolism’.Bone Marrow Transplantation (2007) 40, 225–233; doi:10.1038/sj.bmt.1705718; published online 28 May 2007 [ABSTRACT FROM AUTHOR]

A study was conducted to compare the efficiency and toxicity of two peripheral blood stem cell (PBSC) mobilization procedures for newly diagnosed patients with multiple myeloma. Patients from group 1 (n=51) were treated by high-dose cyclophosphamide (HD-CY) plus G-CSF (5 μg/kg/day), and the second group (n=31) by VAD regimen plus G-CSF administration (10 μg/kg/day). Successful mobilization, defined by a minimal count of 2.5 × 106 CD34+ cells/kg collected, was achieved in 96 and 90% of patients in groups 1 and 2, respectively (P=0.15). The mean peripheral blood CD34+ cells concentration and the mean CD34+ cells/kg collected were higher in group 2 than in the group 1 (P=0.05). The mean number of leukaphereses necessary to collect a count of 2.5 × 106 CD34+ cells/kg was reduced in group 2 compared to group 1. Adverse events, blood products consumption and time spent in the hospital were significantly greater after HD-CY. In conclusion, VAD plus a G-CSF dose of 10 μg/kg administration seems preferential to HD-CY plus a G-CSF dose of 5 μg/kg for PBSC collection because of equivalent or better efficiency in stem cell mobilization, strong favorable toxicity profile and reduced cost.Bone Marrow Transplantation (2006) 37, 725–729. doi:10.1038/sj.bmt.1705308; published online 6 March 2006 [ABSTRACT FROM AUTHOR]

Familial haemophagocytic lymphohistiocytosis (FHLH) is a genetic disorder caused by defective lymphocyte cytotoxicity, resulting in impaired lymphocyte homeostasis and macrophage infiltration of solid tissues and bone marrow, with extensive haemophagocytosis. It is invariably fatal unless treated by allogeneic haematopoietic stem cell transplantation (HSCT). In a retrospective analysis of 11 cases of FHLH, transplanted in one centre between January 1999 and December 2003, it was found that host T cell expansion occurred early after HSCT in a setting of a viral infection (cytomegalovirus and Epstein–Barr virus respectively) in two cases who received T cell-depleted HSCT. Transient recurrence of clinical and biological manifestations of FHLH was observed, despite evidence for donor cell engraftment. Secondary development of donor T cells led to stable mixed chimaerism and sustained remission of FHLH. Detection of host-derived T cells soon after HSCT in a patient with FHLH should thus not mistakenly be taken as a manifestation of graft rejection. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many hematologic malignancies and inherited disorders of the hematopoietic system. Ex vivo T-cell depletion (TCD) of the graft and post-transplantation immunosuppression efficiently prevents the development of GvHD in no- MHC-identical settings. However, the consequence of these non-specific strategies is a long-lasting immunodeficiency associated with increased incidence of disease relapse, graft rejection and reactivation of viral infections. Donor lymphocyte infusion, which is used for treating leukemic relapse after allogeneic HSCT, can result in severe GvHD. Several strategies are being optimized specifically to inactivate anti-host T cells while preserving anti-leukemic or anti-microbial immunocompetence. Based on the ex vivo or in vivo elimination of anti-host T cells, or on the modulation of their anti-host activity, these approaches, which have been explored extensively in pre-clinical studies and tested in some preliminary clinical trials, are discussed in this paper. [ABSTRACT FROM AUTHOR]

Haemopoietic stem-cell transplantation is a life-saving treatment for severe combined immune deficiency. However, there has been little long-term follow-up of this treatment. There is evidence for the persistance of partial immunodeficiency associated with significant infections, including severe human papillomavirus (HPV) disease. We did a retrospective analysis of severe HPV disease in a group of 41 patients with severe combined immune deficiency from one centre who were alive 10 years or longer after haemopoietic stem-cell transplantation. Nine of the 41 patients had extensive chronic HPV disease limited to the skin, with a median onset at 8 years after transplantation. Four had lesions typical of epidermodysplasia verruciformis, a rare genodermatosis. Transplant characteristics, immune status, and chimerism of these nine patients did not differ significantly from those of the other patients. The nine patients with HPV disease had severe combined immune deficiency associated with either common gammac receptor cytokine subunit or Janus kinase-3 (JAK-3) deficiency. By contrast, patients with other forms of severe combined immune deficiency did not have any signs of HPV disease. That genetic causes are the only predisposing factor to be identified for severe combined immune deficiency, suggests that natural-killer cells or gammac/JAK-3-dependent signalling in keratinocytes could have a role in anti-HPV immunity. [ABSTRACT FROM AUTHOR]

Hematological inherited diseases can be cured by hematopoietic stem cell transplantation (HSCT) from an human leukocyte antigen (HLA)-identical sibling donor (MSD), but the outcome of unrelated donors (URD) or haploidentical donors (HMD) has been a cause of concern. In all, 94 children affected with inherited diseases underwent HSCT at a single center using MSD (group A, n = 31), URD (group B, n = 23) or HMD (group C, n = 40). There was no difference in the rate of engraftment or in the incidence of grades III—IV acute graft-versus-host disease (GVHD) between the groups. Survival rate was 80.6% in group A, 62.5% in group B and 47.5% in group C (P = 0.023). In group B, survival rate was 73.7% in the subgroup with zero or one class I mismatch, and 25% in the subgroup with two or more class I mismatches (P = 0.04). In group C, survival rate was 83.3% in the 9/10-identical subgroup, 64.3% in the seven or 8/10 subgroup, and 25% in the five or 6/10 subgroup (P = 0.0007). Thus, engraftment, incidence of GVHD and survival are similar in recipients of grafts from MSD, URD with 0–1 class I-mismatch, or HMD with at least 7/10 HLA matches. The low success of HSCT using more disparate donors suggests reserving them for patients with very poor prognosis. [ABSTRACT FROM AUTHOR]

Background: Transplantation of allogeneic haemopoietic stem cells can cure several primary immunodeficiencies. This European report focuses on the long-term results of such procedures done between 1968 and December, 1999, for primary immunodeficiencies.Methods: The report includes data from 37 centres in 18 countries, which participated in a European registry for stem-cell transplantation in severe combined immuno deficiencies (SCID) and in other immunodeficiency disorders (non-SCID). 1082 transplants in 919 patients were studied (566 in 475 SCID patients, 512 in 444 non-SCID patients; four procedures excluded owing to insufficient data). Minimum follow-up of 6 months was required.Findings: In SCID, 3-year survival with sustained engraftment was significantly better after HLA-identical than after mismatched transplantation (77% vs 54%; p=0.002) and survival improved over time. In HLA-mismatched stem-cell transplantation, B(-) SCID had poorer prognosis than B(+) SCID. However, improvement with time occurred in both SCID phenotypes. In non-SCID, 3-year survival after genotypically HLA-matched, phenotypically HLA-matched, HLA-mismatched related, and unrelated-donor transplantation was 71%, 42%, 42%, and 59%, respectively (p=0.0006). Acute graft versus host disease predicted poor prognosis whatever the donor origin except in related HLA-identical transplantation in SCID.Interpretation: The improvement in survival over time indicates more effective prevention and treatment of disease-related and procedure-related complications--eg, infections and graft versus host disease. An important factor is better prevention of graft versus host disease in the HLA-non-identical setting by use of more efficient methods of T-cell depletion. For non-SCID, stem-cell transplantation can provide a cure, and grafts from unrelated donors are almost as beneficial as those from genetically HLA-identical relatives. [ABSTRACT FROM AUTHOR]

Les de´ficits immunitaires he´re´ditaires constituent un ensemble de maladies au pronostic souvent se´ve`re. Le traitement actuel : l'allogreffe de cellules souches he´matopoi¨e´tiques est susceptible, dans un nombre important de cas, d'apporter un be´ne´fice clinique. Cependant, les re´sultats des greffes effectue´es a` partir de donneurs qui ne sont pas HLA ge´ne´tiquement identiques, comportent un risque non ne´gligeable d'e´chec de reconstitution immunologique partielle. La connaissance re´cente de la plupart des ge`nes implique´s dans les de´ficits immunitaires he´re´ditaires ouvre la perspective de the´rapie ge´nique. Les de´ficits immunitaires combine´s se´ve`res caracte´rise´s par un de´faut de de´veloppement des lymphocytes T constituent une situation privile´gie´e du fait de la possibilite´ d'induire une prolife´ration importante des pre´curseurs lymphocytaires une fois que le ge`ne the´rapeutique est introduit dans les pre´curseurs de la moelle osseuse. Ce concept a e´te´ applique´ avec succe`s au traitement du de´ficit immunitaire combine´ se´ve`re lie´ a` l'X. Ces re´sultats prometteurs me´ritent ne´anmoins confirmation par l'observation des patients sur le long terme. On peut espe´rer e´tendre l'application de ce type de traitement au moins a` d'autres formes de de´ficit immunitaire combine´ se´ve`re. [Copyright 2002 Elsevier]

Following gene therapy of SCID-X1 using murine leukemia virus (MLV) derived vector, two patients developed leukemia owing to an activating vector integration near the LMO2 gene. We found that these integrations reside within FRA11E, a common fragile site known to correlate with chromosomal breakpoints in tumors. Further analysis showed that fragile sites attract a nonrandom number of MLV integrations, shedding light on its integration mechanism and risk-to-benefit ratio in gene therapy.Gene Therapy (2006) 13, 1057–1059. doi:10.1038/sj.gt.3302752; published online 2 March 2006 [ABSTRACT FROM AUTHOR]

Summary:Donor potential to exert NK cell alloreactivity has been shown to confer survival advantage in haploidentical hematopoietic cell transplantation for hematological malignancies. We investigated killer immunoglobulin receptor (KIR) ligand incompatibility in 40 children receiving haploidentical transplantation for primary immunodeficiencies. The conditioning regimen consisted of busulfan and cyclophosphamide. T-cell depletion of the graft used complement-dependent lysis or CD34+selection. Two patients died in the first month. The remaining 38 patients were divided into those with (n=13) and those without (n=25) donor potential to exert NK cell alloreactivity. Engraftment was similar in the two groups (61.5 and 64%, respectively). The incidence of grade II-IV acute graft-versus-host disease (GVHD) tended to be lower in the group with donor potential to exert NK cell alloreactivity, but the difference was not significant. In conclusion, in this series of patients with primary immunodeficiencies, donor potential to exert NK cell alloreactivity was not associated with significant advantages in engraftment and prevention of acute GVHD.Bone Marrow Transplantation (2004) 34, 945-947. doi:10.1038/sj.bmt.1704663 Published online 18 October 2004 [ABSTRACT FROM AUTHOR]

A correction to the article "Fragile sites are preferential targets for integrations of MLV vectors in gene therapy," in the previously published issue is presented.

OBJECTIVES: Familial hemophagocytic lymphohistiocytosis (FHLH) is a genetically determined disorder characterized by the early onset of fever, hepatosplenomegaly, central nervous system disease, thrombocytopenia, coagulation disorders, and hemophagocytosis. It is caused by genetic defects that impair T cell-mediated and natural cytotoxicity. Chemotherapy- or immunotherapy-based treatments can achieve remission. Hematopoietic stem cell transplantation (HSCT), however, is the only curative option, but optimal modalities and long-term outcome are not yet well known. METHODS: We retrospectively analyzed the outcome of HSCT that was performed in 48 consecutive patients who had FHLH and were treated in a single center between 1982 and 2004. RESULTS: The overall survival was 58.5% with a median follow-up of 5.8 years and extending to 20 years. A combination of active disease and haploidentical HSCT had a poor prognosis because in this situation, HLH disease is more frequently associated with graft failure. Twelve patients received 2 transplants because of graft failure (n = 7) or secondary graft loss that led to HLH relapse (n = 5). Transplant-related toxicity essentially consisted in veno-occlusive disease, which occurred in 28% of transplants and was associated with young age, haploidentical transplantation, and the use of antithymocyte globulin (ATG) in the conditioning regimen. A sustained remission was achieved in all patients with a donor chimerism > or = 20% of leukocytes. Long-term sequelae were limited, because only 2 (7%) of 28 patients experienced a mild neurologic disorder. CONCLUSIONS: This survey demonstrates the long-term efficacy of HSCT as a cure of FHLH. HSCT preserves quality of life. It shows that HSCT should be performed as early as a complete remission has been achieved. Additional studies are required to improve the procedure and reduce its toxic effects. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To evaluate the occurrence of autoimmune and inflammatory complications in Wiskott-Aldrich syndrome (WAS) and to determine risk factors and the prognosis of such complications with the aim of improving the definition of treatment options. METHODS: We reviewed the records of 55 patients with WAS evaluated at Necker-Enfants Malades Hospital (Paris) from 1980 to 2000. RESULTS: Forty patients (72%) had at least 1 autoimmune or inflammatory complication. Autoimmune hemolytic anemia was detected in 20 cases (36%); in all cases, onset occurred before the age of 5 years. Other complications included neutropenia (25%), arthritis (29%), skin vasculitis (22%), cerebral vasculitis (7%), inflammatory bowel disease (9%), and renal disease (3%). The median survival of the entire population was 14.5 years. Two autoimmune complications and 1 biological factor were predictive of a poor prognosis in this population: autoimmune hemolytic anemia, severe thrombocytopenia recurring after splenectomy, and high serum immunoglobulin M (IgM) levels before splenectomy. Autoimmune hemolytic anemia was significantly more observed in patients with high serum IgM level. CONCLUSIONS: High serum IgM concentration before splenectomy was identified as a risk factor for autoimmune hemolytic anemia; however, it must be confirmed. Autoimmune hemolytic anemia and severe thrombocytopenia recurring after splenectomy were 2 indicators of a poor prognosis. Those results suggest that patients with WAS and IgM levels more than mean + 2 standard deviations before splenectomy should be placed under strict surveillance. Furthermore, severe autoimmune complications should lead, as early as possible, to hematopoietic stem cell transplantation using the best available donor. [ABSTRACT FROM AUTHOR]